Variable Dynamic Mode Decomposition for Estimating Time Eigenvalues in Nuclear Systems

We present a new approach to calculating time eigenvalues of the neutron transport operator (also known as α eigenvalues) by extending dynamic mode decomposition (DMD) allow for nonuniform steps. The method, called variable (VDMD), is shown be accurate when computing systems that were infeasible with DMD due large separation in timescales (such those occur delayed supercritical systems). an infinite medium problem neutrons, and consequently having multiple, very different relevant timescales, are computed. Furthermore, VDMD similar accuracy original other where previously studied can used.